542 THE ANATOMY OF INVERTEBRATED ANIMALS. 



Thus far, although the organization of Sagitta is very 

 peculiar, it presents analogies both with the JVematoidea and 

 with the Annelida. But its development, as described by 



I — -<>--. <2 



f^ 



Fig. 154. — Sagitta bipunctata.—a, the head, with its eyes and appendages ; 5, the 

 anus ; c, the ovary ; d, the testicular chambers. 



Kowalewsky, 1 is, in some respects, unlike anything at pres- 

 ent known in either of these groups. Yelk-division takes 

 place as usual, and converts the eggs into a vesicular morula, 



1 " Memoires de l'Academie Imperiale des Sciences de St.-Petersbourg," 

 18*1. 



